Serratella albostriata

General appearance
Body size small medium up to about 4mm long (excluding antennae & cerci)
Body color reddish-brown with a wide & pale medial longitudinal stripe on thoracic nota in late larval stage. Cream yellow in early stage.

Head
The details for mouthparts illustrated in the following pictures
Antenna long about 1.5 times of head width; whorls of setae present on each segment of filaments

Thorax
Color reddish-brown with a wide & pale medial longitudinal stripe on thoracic nota in late larval stage. In early stage, cream yellow to yellowish brown with numerous dark brown marks
All of legs robost covered by dense hairs, a whorl of long setae across forefemora dorso-submedially.

Abdomen
Abdominal segments IV - IX with postero-lateral projection
Imbricated gills III - VII: III - VI similar, but VII smaller
Three caudal filaments subequal in length about half of body length; dark band present across filaments medially & terminally

Legs

 

Its mouthparts of labrum, mandibles, maxillae and labium are illustrated as follow (hypopharynx is excluded).

Labrum

Maxillae

Mandibles

Labium

 

Distribution:
In Hong Kong, specimens are recorded from Tai Tso Stream (Tai Mo Shan), Shing Mun, Tai Po Kau Forest Stream, Hok Tau and Chuen Lung.

Habitat: Larvae are found in shaded riffles associated with sand and gravel substrates in shallow and moderate to fast flowing streams.

Reference: Tong, X. & Dudgeon, D. (2000). Ephemerellidae (Insecta: Ephemeroptera) from Hong Kong, China, with descriptions of two new species. Aquatic Insects 22: 197-207.

Remarks: Larvae ain't good swimmers, control of movement is facilitated by undulation of abdomen.